JPH0762057A - Urethane oligomer and active energy beam-curing urethane resin composition with the same as curing component - Google Patents

Abstract

PURPOSE:To provide the subject new oligomer capable of giving cured resin products excellent in both tensile strength and elongation, high in Young's modulus, good in resistance to wear and contamination, also short in tack free time in curing, and to provide the subject resin composition containing this oligomer as curing component. CONSTITUTION:The objective urethane oligomer is represented by =O-O...O= (where, =, O,-, and ... denote active hydrogen-contg. (meth)acrylate-based monomer unit, polyisocyanate unit, low-molecular weight polyol <=300 in molecular weight, and high-molecular weight polyol >=500 in molecular weight, respectively). The other objective active energy beam-curing urethane resin composition contains this oligomer as curing component.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel urethane oligomer and an active energy ray-curable urethane resin composition containing the oligomer as a curable component.

[Prior art]

[0002] Urethane acrylate oligomers have ultraviolet curability and are useful as film-forming raw materials such as paints, inks, protective coating agents, and adhesives, like epoxy acrylate oligomers and polyester acryl oligomers.

For convenience of description below and for intuitive understanding of the molecular structure, an active hydrogen-containing (meth) acrylate-based monomer unit is represented by "=", if necessary.
The polyisocyanate unit will be represented by "○", the low molecular weight polyol will be represented by "-", and the high molecular weight polyol will be represented by "...".

Japanese Patent Application Laid-Open No. 57-17 filed by the present applicant
No. 2915 discloses a molecular weight of 500 to 200 containing 1,4-cyclohexanedimethanol as a polyhydric alcohol.
A photocurable urethane acrylic resin composition using a prepolymer obtained by reacting a low molecular weight polyester resin of 0 with a diisocyanate compound and then reacting with an active hydrogen-containing acrylic monomer is disclosed. The structure of the obtained prepolymer is = ○ …… ○ = (2).

Japanese Patent Application Laid-Open No. 57-65 filed by the present applicant
No. 714 (Japanese Patent Publication No. 2-10166) discloses a polyester polyol having a molecular weight of about 1000 to 5000.
It shows a photocurable resin composition using a prepolymer obtained by reacting (A) with a polyvalent isocyanate compound (B) and then reacting with an active hydrogen-containing acrylic monomer (C). In Example 1, 2 mol of (A) was reacted with 3 mol of (B), and then 2 mol of (C) was reacted.
The structure of the obtained prepolymer is = ○ …… ○ …… ○ = (3).

JP-A-3-244618 discloses a polyether glycol (a), a diisocyanate compound.
(b) is a UV-curable urethane compound obtained by reacting a dihydric alcohol (c) having a molecular weight of 300 or less with a vinyl unsaturated monomer (d) having a hydroxyl group. Here, the polyether glycol unit is a soft segment, and hard segment of continuous urethane bond composed of dihydric alcohol and diisocyanate is located at both ends thereof. That is, the structure of this prepolymer is as follows: = ○-○ ...... ○-○ = (4) = ○-○-○ ...... ○-○-○ = (5) = ○-○-○-○ ...... ○- ○-○-○ = (6).

JP-A-4-77515 discloses that a polyol having a molecular weight of 1,000 to 10,000, a diisocyanate compound, a dihydric alcohol having a molecular weight of 300 or less, and a vinyl unsaturated monomer having a hydroxyl group are reacted to obtain four compounds. Radiation curable oligomers are shown. The structure of this oligomer is: ○○○○○○○○ (7) = ○ － ○ …… ○ － ○ …… ○ － ○ ＝ (8) ＝ ○ － ○ …… ○ － ○ …… ○ － ○ …… ○ − ○ = (9) etc.

[0008]

SUMMARY OF THE INVENTION
According to the Examples, the photocurable urethane acrylic resin composition disclosed in JP-A-172915 has a tensile strength-elongation balance of 150 kg / cm ² -310% and 200 kg / cm ^2.
-180%, 240kg / cm ² -90%, 230kg / cm ² -1
60% and 240 kg / cm ² -130%, and both strength and elongation tend to be insufficient. In addition, there is a problem that the strength is further reduced if the elongation is to be maximized.

JP-A-57-65714 (Japanese Patent Publication No.
No. 10166), a photocurable resin composition using a prepolymer disclosed in JP-A-10166) is an example in which 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate is used in combination with the prepolymer as a monofunctional polymer. The tensile strength-elongation balance is 1
^{80kg / cm 2 -380%, 120kg} / cm 2 -310%, 14
0kg / cm ² -430%, 120kg / cm ² -360%, 75kg
/ cm ² -470%, and although satisfactory results are obtained in terms of elongation, there is a problem that tensile strength is insufficient. When not using a monofunctional polymer together,
Tensile strength, Young's modulus, and elongation tend to decrease significantly. Further, according to additional tests by the present inventors, the photocurable resin composition of the publication has a disadvantage that the tack-free time is 5 seconds or more, which is long for a photocurable resin composition.

The UV-curable urethane compound disclosed in JP-A-3-244618 has a tensile strength-elongation balance of 230 kg / cm ² -450%, according to the examples.
It is 250 kg / cm ² -440%, and although satisfactory results are obtained in terms of elongation, there is a problem that tensile strength is insufficient.

On the other hand, according to the examples, the radiation-curable oligomer disclosed in JP-A-4-77515 has a tensile strength-elongation balance of 450 kg / cm ² -80.
^{0%, 480kg / cm 2 -760} %, 360kg / cm 2 -700
%, 470 kg / cm ² -550%, 440 kg / cm ² -620%
Therefore, both the tensile strength and the elongation are extremely excellent. However, the cured film obtained from this oligomer has the disadvantage that the Young's modulus is as low as 15 to 55 kg / cm ² . Further, according to an additional test by the present inventors, the cured film has insufficient abrasion resistance in the Taber abrasion test, for example, 10 to 22 mg, and has insufficient stain resistance (drawing with a quick-drying oil-based ink). However, when left at room temperature for 24 hours and then wiped off with ethanol, traces of lines are clearly left), and there is also a disadvantage that dirt or dust cannot be easily cleaned.

Under such circumstances, the present invention is excellent in both tensile strength and elongation, has a large Young's modulus, good abrasion resistance and stain resistance, and has a short tack-free time during curing. Another object of the present invention is to provide a urethane-based oligomer, and an active energy ray-curable urethane-based resin composition containing the urethane-based oligomer as a curable component.

[0013]

The urethane oligomer of the present invention comprises an active hydrogen-containing (meth) acrylate monomer unit "=", a polyisocyanate unit "O", and a low molecular weight polyol having a molecular weight of 300 or less "-". ], When a high molecular weight polyol having a molecular weight of 500 or more is represented by "...", it is represented by the formula: = ○-○ ... ○ = (1).

The active energy ray-curable urethane resin composition of the present invention contains the above urethane oligomer as a curable component.

The present invention will be described in detail below.

The urethane oligomer of the present invention is represented by the above formula (1). Each component constituting this oligomer will be described in order.

Examples of the active hydrogen-containing (meth) acrylate-based monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, tripropylene glycol (meth) acrylate, and 1,4-butylene glycol mono. (Meth) acrylate, 2-hydroxy-3-chloropropyl (meth) acrylate, glycerol mono (meth) acrylate, glycerol di (meth) acrylate, glycerol methacrylate acrylate and the like are used.

As the polyisocyanate, for example,
2,4- or 2,6-tolylene diisocyanate, m
-Or p-xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane-4,4'-
Diisocyanate or a modified product or polymer thereof, hexamethylene diisocyanate, isophorone diisocyanate, 1,4-tetramethylene diisocyanate, naphthalene diisocyanate or the like is used.

Examples of the low molecular weight polyol having a molecular weight of 300 or less include ethylene glycol, diethylene glycol, triethylene glycol, 1,2- or 1,3-propylene glycol, 1,3- or 1,4.
-Butanediol, 1,5-pentanediol, 1,6
-Hexanediol, neopentyl glycol and the like are used.

As the high molecular weight polyol having a molecular weight of 500 or more, among polyether type polyols, polyester type polyols, polycarbonate type polyols, acrylic polyols, polybutadiene type polyols, polyolefin type polyols and the like, those having a molecular weight of 500 or more, particularly 500 When the molecular weight is less than 500, the elongation of the cured product becomes insufficient.

The urethane oligomer of the present invention typically comprises 2 mol of polyisocyanate and 1 mol of low molecular weight polyol in the presence of a suitable solvent in an atmosphere of an inert gas such as nitrogen gas at a temperature of 50 to 95 ° C. To about 1 degree, then add 1 mol of high molecular weight polyol to react,
Further, a method is employed in which 1 mol of polyisocyanate is added and reacted, and finally 2 mol of active hydrogen-containing (meth) acrylate monomer is added and reacted at a temperature of about 50 to 80 ° C. A catalyst may be optionally present in the reaction. However, the reaction molar ratio of each component described above represents a typical case.

In addition to the above method, 3 mol of polyisocyanate and low molecular weight polyol 1
A method of reacting with 1 mol of a high molecular weight polyol, and then reacting with 2 mol of an active hydrogen-containing (meth) acrylate-based monomer;
A method in which 1 mol of a low-molecular-weight polyol and 2 mol of an active hydrogen-containing (meth) acrylate-based monomer are added and reacted, and 2 mol of polyisocyanate and an active hydrogen-containing (meth)
A method of reacting with 2 mol of an acrylate-based monomer, then reacting with 1 mol of a high-molecular-weight polyol, and further adding 1 mol of a polyisocyanate and 1 mol of a low-molecular-weight polyol to carry out a reaction is also adopted.

The total charged molar ratio of each component is based on 3 mol of polyisocyanate, 1 mol of low molecular weight polyol, 1 mol of high molecular weight polyol, and 2 mol of active hydrogen-containing (meth) acrylate-based monomer. Variations of about 3.5 mol, low molecular weight polyol 0.5 to 1.5 mol, high molecular weight polyol 0.5 to 1.5 mol, and active hydrogen-containing (meth) acrylate-based monomer 1.5 to 2.5 mol are allowed.

As a result, a urethane oligomer represented by the following formula is obtained. However, in the following formula, as described above, the active hydrogen-containing (meth) acrylate-based monomer unit is “=”, the polyisocyanate unit is “◯”, and the low molecular weight polyol having a molecular weight of 300 or less is “−”. , A high molecular weight polyol with a molecular weight of 500 or more
... ". ＝ ○ － ○ …… ○ ＝ (1)

The active energy ray-curable urethane resin composition of the present invention contains the above urethane oligomer as a curable component.

When this composition is cured by electron beam irradiation, no photopolymerization initiator is usually used, but when it is cured by ultraviolet irradiation, a photopolymerization initiator is added. Examples of the photopolymerization initiator include 1-hydroxycyclohexyl phenyl ketone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin phenyl ether, benzyldiphenyl disulfide, azobisisobutyronitrile, and the like. Dibenzyl, diacetyl, anthraquinone, naphthoquinone, benzophenone, pivaloin ethyl ether, benzoyl peroxide, benzyl ketal, 1,1-dichloroacetophenone, para-t-butyldichloroaetophenone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,2-diethoxyacetophenone, 2,2-
Dimethoxy-2-phenylacetophenone, 2,2-dichloro-4-phenoxyacetophenone, Michler's ketone, phenylglyoxylate, α-hydroxyisobutylphenone, dibezosparone, benzophenone amine system, 1- (4-isopropylphenyl) -2-hydroxy- 2-Methylpropanone, 2-methyl- [4- (methylthio) phenyl] -2-morpholino-1-propanone and the like are used, and the compounding amount thereof may be about 1 to 10% by weight based on the whole composition. Many.

Various other additives may be added to the composition. Examples of additives include fillers, dyes and pigments, oils, plasticizers, waxes, desiccants, dispersants, wetting agents, emulsifiers, gelling agents, stabilizers, defoamers, leveling agents, thixotropic agents, etc. Can be given.

The composition also contains styrene, vinyltoluene, α-methylstyrene, methylmethacrylate,
Methyl acrylate, ethyl acrylate, acrylonitrile, vinyl acetate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, cyclohexyl acrylate, dicyclopentadiene acrylate, N-vinylpyrrolidone, furfuryl acrylate, carbitol acrylate, benzyl acrylate, butoxyethyl acrylate. , Allyl acrylate, phenoxyethyl acrylate, acryloxyethyl phosphate, 2-vinyl pyridine, and other various monomers can be blended in desired amounts.

After the composition is applied to an object, it is cured by irradiation with ultraviolet rays or electron beams. A high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a xenon lamp, a metal halide lamp, a chemical lamp, a black light and the like are used as a light source for ultraviolet irradiation. The irradiation time varies depending on the type of the light source, the distance between the light source and the coating surface, and other conditions, but at most several tens of seconds is sufficient, usually several seconds, and in some cases, a fraction of a second. After irradiation with ultraviolet rays, heating may be performed as necessary to achieve complete curing. In the case of electron beam irradiation, for example, an electron beam having an energy in the range of 50 to 1000 KeV may be used and the irradiation amount may be 2 to 5 Mrad.

The urethane acrylate-based oligomer of the present invention and the active energy ray-curable resin composition containing the oligomer are a coating material, an ink, a protective coating agent,
It is useful as various film forming materials such as anchor coating agents, magnetic powder coating binders, sandblast coatings, adhesives, and plate materials.

[0031]

Since the urethane-based oligomer of the present invention has a unique molecular structure, a film obtained from an active energy ray-curable urethane-based resin composition containing the oligomer as a curable component has a tensile strength, elongation, In addition to having a large Young's modulus, it has good wear resistance and stain resistance. There is also an advantage that the tack-free time during curing is short.

[0032]

EXAMPLES The present invention will be further described with reference to examples. Hereinafter, "parts" and "%" are shown on a weight basis.

Example 1 <Urethane-based oligomer> 290.3 g (1.66 mol) of tolylene diisocyanate was placed in a four-necked flask equipped with a thermometer, a stirrer, a water-cooled condenser, and a nitrogen gas blowing port.
Neopentyl glycol 57.9g (0.55mol), toluene
274.8 g was charged and reacted at an internal temperature of 80 to 90 ° C. for 5 hours, and when the residual isocyanate group became 15%, 347.3 g of polytetramethylene glycol having a molecular weight of 650 (0.
(53 mol) and 0.15 g of dibutyltin dilaurylate were added, and the mixture was further reacted for 5 hours. 5% residual isocyanate groups
Was maintained at 60 to 70 ° C., 129.0 g (1.11 mol) of 2-hydroxyethyl acrylate was added and reacted for 4 hours, and the reaction was stopped when the residual isocyanate group became 0.5%.

The NMR chart of the urethane oligomer thus obtained is shown in FIG. 1, and the IR chart is shown in FIG. This urethane-based oligomer has a structure of = ○-○ ... ○ = (1).

<Active energy ray-curable urethane resin composition> Into the composition containing the urethane oligomer obtained above (100 parts of resin content), 1-hydroxycyclohexyl phenyl ketone as a photoinitiator ("Ciba Geigy Co." 5 parts of Irgacure 184 ") was added and mixed to prepare an ultraviolet curable resin liquid. This resin solution is applied on a polyester film with an applicator to a thickness of 100 μm, dried with hot air at a temperature of 75 ° C for 10 minutes, and then a high pressure mercury lamp of 80 W / cm is used to convey the resin from a height of 20 cm to a conveyor of 5 m / min. One pass of UV irradiation was performed at a speed to form a cured film. The tack-free time was as short as 0.5 seconds.

The formed film was peeled from the polyester film to prepare a test piece having a width of 10 mm and a length of 25 mm, and the tensile strength, Young's modulus and elongation were measured by an autograph under the condition of a tensile speed of 20 mm / min. . The results are shown below. Tensile strength 382 kg / cm ² Young's modulus 153 kg / cm ² Elongation 363%

With respect to the above coating, the abrasion resistance was measured by using a Taber abrasion tester and the stain resistance was tested. The results are shown below. For stain resistance, draw a line with commercially available red and black quick-drying oil-based ink,
After leaving it at room temperature for 24 hours, it was wiped off with ethanol. When there was no line mark, it was judged as ◯, when the line mark was slightly left, it was judged as Δ, and when it was clearly left, it was judged as x. Abrasion resistance 0.6 mg (load 1000 g, wheel CS-10, rotation speed 500
rpm) Stain resistance Black quick-drying oil-based ink ○ Red quick-drying oil-based ink ○

Examples 2 to 3 A urethane-based oligomer was produced in the same manner as in Example 1 except that the following components were used, and the cured film was formed by irradiation with ultraviolet rays.

[0039] Example 2 - Charge components and total molar ratio of isophorone diisocyanate 3 mole of neopentyl glycol 1 mol molecular weight 650 polytetramethylene glycol 1 mol of 2-hydroxyethyl acrylate 2 moles and measurement results of tensile strength 360 kg / cm ² Young Rate 124 kg / cm ² Elongation 420% Abrasion resistance 1.4 mg (load 1000 g, wheel CS-10, rotation speed 500
rpm) Stain resistance Black quick-drying oil-based ink ○ Red quick-drying oil-based ink ○

Example 3 Charge components and total charge molar ratio xylylene diisocyanate 3 mol neopentyl glycol 1 mol polytetramethylene glycol having a molecular weight of 650 1 mol 2-hydroxyethyl acrylate 2 mol ・ measurement result tensile strength 343 kg / cm ² Young's modulus 118 kg / cm ² Elongation 382% Abrasion resistance 1.7 mg (load 1000 g, wheel CS-10, rotation speed 500
rpm) Stain resistance Black quick-drying oil-based ink ○ Red quick-drying oil-based ink ○

Comparative Example 1 A four-necked flask equipped with a thermometer, a stirrer, a water-cooled condenser, and a nitrogen gas inlet was placed in a nitrogen stream under adipic acid.
1.0 mol, ethylene glycol 0.56 mol and 1,4-
Charge 0.56 mol of butanediol and heat to 2 with stirring.
The mixture was heated at 30 ° C. for 17 hours, and when the acid value reached 0.6 KOHmg / g, the reaction was stopped and the mixture was cooled. Hydroxyl value is 55.6 KOHmg / g
Met. The number average molecular weight of this polyester polyol was 2080 as measured by high performance liquid chromatography.

2 mol of this polyester polyol was mixed with 3 mol of a mixture of 2,6-tolylene diisocyanate and 2,4-tolylene diisocyanate in a weight ratio of 20% / 80%, and an appropriate amount of ethyl acetate was added. After the addition, the reaction was carried out at a temperature of 60 to 90 ° C, and when the remaining isocyanate groups reached 1.8%, 2.06 mol of 2-hydroxyethyl acrylate and monomethyl ether hydroquinone were added.
0.04% was added and the reaction was carried out at 50 ° C. for 11 hours, and the reaction was stopped when the residual isocyanate groups reached 0.2%. The hydroxyl value was 3.3 KOHmg / g.

The obtained urethane-based oligomer has a structure of ∘∘∘∘∘∘ = (3).

100 parts of the urethane oligomer obtained above was added with 3 parts of benzoin isopropyl ether to form a uniform resin solution, and this resin solution was applied onto a polyester film with an applicator to a thickness of 100 μm, and the temperature was adjusted to 7
After drying with hot air at 5 ° C for 10 minutes, high pressure mercury lamp 80
A single pass of UV irradiation was performed from a height of 20 cm at a conveyor speed of 5 m / min using W / cm to form a cured film.

Test pieces were prepared in the same manner as in Example 1, and the tensile strength, Young's modulus and elongation were measured. The results are shown below. Tensile strength 75 kg / cm ² Young's modulus 40 kg / cm ² Elongation 120%

[0046]

Since the urethane oligomer of the present invention has a unique molecular structure, a film obtained from an active energy ray-curable urethane resin composition containing the oligomer as a curable component has a tensile strength and elongation In addition to high degree and Young's modulus, it has good wear resistance and stain resistance. There is also an advantage that the tack-free time during curing is short.

[Brief description of drawings]

1 is the N of the urethane-based oligomer obtained in Example 1. FIG.
It is an MR chart.

2 is the I of the urethane-based oligomer obtained in Example 1. FIG.
It is an R chart.

Claims (2)

[Claims] 1. An active hydrogen-containing (meth) acrylate-based monomer unit is "=", a polyisocyanate unit is "○",
When a low molecular weight polyol having a molecular weight of 300 or less is represented by "-" and a high molecular weight polyol having a molecular weight of 500 or more is represented by "...", a urethane oligomer represented by the formula: = ○-○ ... ○ = (1). 2. An active energy ray-curable urethane resin composition containing the urethane oligomer according to claim 1 as a curable component.